The present invention relates to adjustable length sport poles for use in hiking, skiing and other outdoor recreational activities, and to coupling mechanisms that may be used in sport poles.
In many outdoor recreational activities, such as skiing and hiking, poles are used for better balance and performance. Skiers, for example, plant ski-poles in the snow to execute turns, maintain their balance, or push-off over flat terrain. Hikers use similar poles to enhance their stability over rough or slippery terrain. Conventional ski-poles are widely used in both alpine and nordic skiing, and hiking-poles are becoming very popular for all levels of hiking.
Ski-poles and hiking-poles are very similar, but they typically have different lengths to accommodate the particular requirements of the different activities. Alpine ski-poles are typically quite long because alpine skiers plant the poles in front of them down the slope of the hill. Hiking-poles, on the other hand, are typically shorter than ski-poles because hikers prefer to have shorter poles for going uphill and hikers generally do not hike down the fall line of steep slopes. Hikers, however, may also prefer to have longer poles for going downhill, or to have one short pole and one long pole for going laterally across sloped hillsides. Also, because hiking-poles may need to be stored during a hike (e.g., while climbing), it is also desirable to fit hiking-poles into a backpack. Thus, to meet the different requirements for ski-poles and hiking-poles with a single pole, it is desirable to adjust the length of the poles.
Conventional adjustable length poles typically have two or three telescoping pole sections with a device to releasably fix one section to an adjoining section. In one conventional pole, an inner pole section is fixed to an outer pole section with an exterior clamp. Such clamps, for example, are permanently attached to the outer pole sections to contract and frictionally engage the smooth outer surface of the inner pole sections. Typical exterior pole clamps are similar to those used on bicycle stems for adjusting the height of bicycle seats. In another conventional adjustable length pole, inner and outer pole sections are fixed together with a locking device having a wedge and an expandable member attached to an end of the inner pole section. The wedge and the expandable member are received in the outer pole section, and the wedge is positioned in the expandable member to distend the expandable member. These locking devices operate by rotating the inner and outer pole sections with respect to one another to drive the wedge into the expandable member. As the wedge drives into the expandable member, the wedge distends the expandable member to press against the inner surface of the outer pole section until the friction between the expandable member and the outer pole section holds the inner and outer pole sections together.
Although conventional adjustable poles are useful for skiing and hiking, the conventional clamp-type and expandable member-type locking assemblies often allow the inner and outer pole sections to slip with respect to one another when large axial loads are placed on the pole. Unfortunately, the largest axial loads are typically placed on the pole when a skier or a hiker is falling, and thus such slippage between the pole sections may render the poles less effective in supporting the user. Such slippage between the pole sections is also inconvenient because the poles may need to be readjusted back to a desired length. Efforts are often made to make adjustable length poles less prone to slipping by tightening the clamps or expandable members with greater force. However, doing so can make it difficult to release the clamps and the expandable members for adjustment, particularly if they are tightened too tight. Additionally, conventional adjustable length poles may be difficult to adjust to a definite length because the clamps and the expandable members may engage any portion of the particular pole section. Therefore, conventional adjustable length poles may have several drawbacks for use as ski-poles and hiking-poles.
The present invention is directed toward adjustable length sport poles and methods of using adjustable length sport poles in for skiing, hiking and other recreational activities. In one embodiment of the invention, an adjustable length sport pole has a first pole section, a second pole section slidably received within the first pole section, and a locking assembly to releasably hold the first and second pole sections together at defined positions.
The locking assembly for releasably coupling the first and second pole sections together has a resilient locking element and a collar that moves between a lock position and a release position with respect to the locking element. In one embodiment, the resilient locking element extends around the second pole section in a plane transverse to the pole axis, and the locking element has an inner dimension less than an outer dimension of the second pole section. The locking element accordingly expands when it is attached to the outer surface of the second pole section to press radially inward against the second pole section. As such, the locking element may snap into detents formed in the outer surface of the second pole section at defined locations along the length of the second pole section when one of the detents is aligned with the locking element.
The collar may have a cavity defined by a retaining surface and a recessed surface, and the locking element is positioned within the cavity. The retaining surface limits the expansion of the locking element when the collar is in the lock position and the locking element is in one of the detents. The retaining surface of the collar accordingly prevents the locking element from disengaging the detent and sliding over the second pole section to prevent axial movement between the first and second pole sections. When the collar is in the release position, the locking assembly allows axial movement between the first and second pole sections to adjust the length of the pole to another defined pole length.
In one particular embodiment, the first and second pole sections are first and second tubes, and the detents in the second pole section are annular grooves around the second tube. The locking element may accordingly be a clip, such as a C-spring or a ring-spring, with a curved inner surface to fit in the annular grooves and a flat outer surface to engage the retaining surface of the collar. Prior to being assembled with the second pole section, the inner diameter of the clip preferably is slightly smaller than the outer diameter of the second pole section so that the clip biases itself against the second pole section. In this embodiment, the clip releasably snaps into the detents as the second pole section moves axially along the first pole section during adjustment.